1. Field of the Invention
The present invention relates to a single-lens reflex camera with a built-in flash.
The present invention also relates to a built-in flash changeover mechanism which makes it possible to attach an external flash to a single-lens reflex camera having another flash built therein.
2. Background of the Invention
Conventionally, a flash is attached over the pentaprism of a single-lens reflex camera every time the flash is used for photography If the flash is heavy, it is coupled to the body of the camera by a special strong coupling device
When a flash is secured over a pentaprism, the joint of the flash and the body of a camera has such a low mechanical strength that the joint is very likely to be damaged when the camera fitted with the flash on the body of the camera is carried. For that reason, the flash needs to be attached and detached to and from the camera body at a place where the flash is used.
The number of photographers who want to perform sophisticated photography of a subject by using not only ambient light around the subject but also auxiliary light has been increasing due to the appearance of high-sensitivity films. Such photographers tend to carry flashes with them all the time.
Since an object at a very small distance is likely to be photographed under flash light by a single-lens reflex camera, it is more desirable to place a flash tube on a vertical plane containing the central optical axis of the camera than to place the flash tube at the side of the camera.
In a single-lens reflex camera of the type with an exchangeable lens, a flash is embedded in the side part of the body of the camera near its front as in a compact camera of the lens shutter type. In a single-lens reflex camera, there is mounted thereon a flash having a flash emitting section which can be protruded from the body of the camera.
Objects in a range from a very small distance to a very large distance are photographed by a single-lens reflex camera, particularly a single-lens reflex camera of the lens exchange type. The lens of the camera of the lens exchange type is often replaced with another on of appropriate focal length For that reason, when a flash is built in the single-lens reflex camera, it is necessary to avoid making its lens barrel intercept light emitted from the flash However, in a conventional single-lens reflex camera, having a flash, a light emitting section is located near; beside the lens of the camera. For that reason, the light from the flash of the conventional single-lens reflex camera does not sufficiently illuminate an object when a long lens barrel is attached to the camera.
When a flash is used to photograph a flower, an insect or the like at a small distance by a single-lens reflex camera, it is desirable to irradiate light upon the object from the central part of the camera. For that reason, the flash is secured over the pentaprism (view ping prism) of the camera by electric contacts provided over the rear of the pentaprism However, the structural strength of the secured portion of the flash is so low that the connecting portion is likely to be damaged It is impossible to photograph an object at a very small distance by a compact camera of the lens shutter type. As for a single-lens reflex camera, it is desirable to easily use a flash to photograph an object at a very small distance. It is desired that a photographer not skilled in single-lens reflex photography can more easily use a flash.
A flash unit may be built into the body of a single-lens reflex camera of the lens exchange type in such a manner that the light emission means of the flash is located in the film rewinding section of the camera or in its pentaprism casing Typically, objects at various distances including extremely small distances and very large distances are photographed by a single-lens reflex camera, particularly for a single-lens reflex camera whose lens is often replaced by other lenses of desired focal lengths. Since the performance of zoom lenses has recently been enhanced, the number of persons who usually do not use a standard lens but instead use such a zoom lens which covers the functions of a wide-angle lens, a medium-distance photographing lens and a telephoto-lens has been increasing. As for zoom lenses in general, the total length of a lens tube does not change even if the focal length of the lens is decreased for wide-angle photography. For that reason, it is necessary to build the flash in the single-lens reflex camera so that the light from the flash is not blocked by the lens barrel.
However, the light emission means of a flash built in such a conventional single-lens reflex camera is protruded nearly upwards from the body of the camera so that the light from the flash is blocked by a long barrel and therefore not enough light is irradiated upon an object to be photographed.
On the other hand, a flash for a large quantity of light is not much needed these days because high-sensitivity films such as the ISO 400 and the ISO 1000 have become available on the market. In addition, there is an increasing desire to reduce the weight of a camera, namely, to make its accessories light and compact.
In the prior art, since the light emission surface of an external flash which is attached to a conventional camera by inserting the attaching foot of the flash into the attaching shoe of the camera is placed nearer an object to be photographed, the attaching foot is placed behind the light emission surface of the external flash.
When a built-in flash is to be used which has a light emission means mounted over and in front of a pentaprism casing and is incorporated in a single-lens reflex camera, the light emission means is protruded up from the pentaprism casing. When the built-in flash is not to be used, the built-in flash is housed in the pentaprism casing.
When the built-in flash of the single-lens reflex camera is in the operational position, namely, the light emission means is protruded up from the pentaprism casing, an external flash cannot be attached to the camera because the attaching foot of the external flash cannot be completely inserted into the attaching shoe of the camera. As a result, a synchronization terminal might not be properly connected.
On yet another point, the automated control of a single-lens reflex camera has been recently so much advanced that the number of pieces of camera control information such as exposure information, film information and flash information, which are given to a photographing person, has become quite large The space required for displaying these items of information has also become large along with the increase in the number of the items of information. For that reason, the use of a large-size display member made of an LCD display panel or the like has lately begun for such a single-lens reflex camera because of the low electric power consumption of the display member However, it is a problem where the large-size display member should be located in the camera.
Since photography is often performed by using a flash these days, the flash is a common requirement. For that reason, various types of single-lens reflex cameras have been devised such as one with a built-in flash, which is protruded from the body of the camera at the time of use of the flash and is retracted into the body except during use for the sake of the convenience of carrying of the camera. Several such built-in flashes are a subject of this application Since an object at a large distance is often photographed by such a single-lens reflex camera these days, a flash with a large quantity of light needs to be provided in the camera. Since the volume of the flash with the large quantity of light is large, the flash occupies a large space in the body of the camera.
However, it has been difficult to provide a large-size display member and a large-size flash in a single-lens reflex camera without degrading its handling and carrying properties.